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Positive to negative photoconductance switching in plasmonic gold nanoparticle networks
No full textInternational audienceThe elaboration of versatile materials in which electrical conduction is tuned by light irradiation is of paramount relevance to such diverse applications as photodetectors, photodiodes, solar cells or light sensors. Although positive photoconductance is increasingly common, systems with negative photoconductance are scarcely reported. In this work, a switching from positive to negative photoconductance is observed upon simple annealing of well-organized networks of gold nanoparticles stabilized by dodecanethiols. The photoconductance properties are investigated experimentally using impedance spectroscopy. The measured Nyquist plots and resonance curves of the impedance are analyzed in terms of equivalent electrical circuits consisting in parallel resistance, capacitance and photoconductance. The positive and negative photo-current conversion efficiencies of the nanoparticles network are estimated k PPC = 389 ± 40 nS.W -1 .cm 2 and k NPC = -241 ± 40 nS.W -1 .cm 2 , respectively. With the aid of density functional theory calculations, the origin of the photoconductance is discussed, at the nanoscale level, in terms of changes of molecular conformation. Such molecular effects assist charge carrier tunneling between first neighbor nanoparticles, and favor the formation of traps introduced by the annealing of the sample. The present work contributes to the understanding of plasmo-electronic properties of hybrid molecule-nanoparticle self-assembled nano-structures
Understanding cultural persistence and change: A replication of Giuliano and Nunn (2021)
No full textInternational audienceGiuliano and Nunn (2021) provide econometric evidence that ancestral climatic variability reduces the current importance of tradition. We conduct a “deep reproduction”, comparing the precise descriptions of the individual‐level regressions in their article with the corresponding code. This analysis uncovers several major inconsistencies, also related to the code not included in their replication package. A published corrigendum addresses some inconsistencies we had also communicated to the Editor of REStud, but several remain, relating to a substantial portion of the observations. A realignment of the code with the text reveals a more nuanced relationship between ancestral climatic variability and tradition
Assessing the non-target effects of herbicides on field margin plant communities after controlling for soil, climate, local context and landscape metrics
No full textInternational audiencePesticides are often identified as one of the major causes of biodiversity decline in farmlands. However, our knowledge about this relationship has mostly being inferred from small to landscape-scale studies, or from indirect indicators of agricultural practices at large scales. Here, we used a national network of more than 500 sites monitored yearly from 2013 to 2018 in France to assess the non-target effects of herbicides on field margin plant communities. We used hierarchical generalized linear models to investigate the effects of practices on plant species richness, plant species evenness, proportion of nature-value plants, and proportion of grasses in field margins, while controlling for a large number of possible confounding effects. The intensity of herbicide use had a negative effect on plant species richness, and on the proportion of nature-value plants. In the margin of cereal fields, there was a negative effect of dicotyledon herbicides on richness and a negative effect of grass herbicides on species evenness. We also identified, in some specific crops, a negative effect of non-herbicide treatments on margin flora richness and on the proportion of nature-value plants. The presence of surrounding grasslands had a consistent favourable effect on richness and on the proportion of nature-value plants in field margins. Finally, situations of risk for pesticides drift had a negative effect on margin flora. This study confirms that reducing herbicide use represents a robust lever to maintain the floristic diversity of field margins, which could be combined with strategies reducing the risk of pesticide drift
Introduction - In the name of nature: Activists, experts, and the law
No full textInternational audienceIn recent decades, there have been growing debates across the world about the protection of the environment and the protection of animals. Thoughthe two issues have separate histories, they have become so entangled today that some consider the ‘Animal question’ to be “at the very heart of the‘Nature question’” (Mason 2007: 204) – determining the place of human beings in the world. They are managed through legislation, administrativerules, and, increasingly, court decisions. The contributions to this special issue of Civilisations try to understand and analyse the way in which humanrelationships to animals or to the environment are shaped – or not – by legal action, and how people make use of juridical frameworks to activelyengage in the protection of nature; how this issue is handled by lawyers, activists, and the state; and how, in other words, nature is ‘judicialised’ inrelation to ecological or ethical concerns and as part of a will to manage it. Most of these contributions were initially presented during a workshoporganised in 2022 in Paris in the frame of the programme Ruling on Nature. Animals and the environment before the Court, funded by the FrenchNational Research Agency (Programme ANR-19-CE03-0006)
Precise relocation of the 14 August 2021 M<sub>w</sub> 7.2 Nippes, Haiti, earthquake sequence using broadband and citizen-hosted short-period seismometers
No full textInternational audienceOn 14 August 2021, the Southern Peninsula of Haiti experienced a Mw 7.2 earthquake, 15 years after the devastating Mw 7.0 event that struck the capital city of Port-au-Prince on 12 January 2010. We use the data from a local temporary broadband seismic network, a national network of low-cost seismometers, and regional seismic networks, together with a probabilistic, global-search, non-linear location method (NLL-SSSTcoherence), to obtain a catalog of 5341 precisely relocated events spanning 20 August 2021 to 6 February 2022, with local magnitudes ranging from 0.5 to 5.6. We compute focal mechanisms for a subset of 73 events through waveform inversion. The catalog can be split into aftershocks directly related to the Nippes earthquake rupture process, and two off-rupture clusters. A first one concerns the Anse-à-Veau-Miragoâne area and corresponds mostly to the aftershock sequence of two Mw 5.3 and 4.9 earthquakes that likely activated a segment of the offshore, south-dipping, Jérémie-Malpasse reverse fault system. A second sequence, offshore Jérémie and clustered close to the offshore trace of that same fault, started immediately after the Nippes mainshock and continued during the entire time interval of the present study. The swarm-like temporal distribution of this sequence, as well as evidence for directional propagation of the epicenters, indicate that it was likely driven by fluid migration. We interpret this seismicity as the result of oblique sub-crustal slip on a south-dipping fault which accounts for oblique convergence between the Gonâve and Caribbean plates in southern Hispaniola. Strain in the crust then partitions between reverse faulting on the Jérémie-Malpasse fault system, strike-slip on the Enriquillo fault, and hybrid faulting in between. Seismic hazard assessment for the region should therefore account for faults other than the Enriquillo fault as potential sources for future earthquakes
Beyond single nanomaterial exposure: investigating the fate of a TiO 2 and CeO 2 nanomaterial mixture in freshwater mesocosms
No full textInternational audienceAssessing the environmental risks of emerging contaminants related to new technologies remains a major challenge due to the diversity of pollutants, their complex interactions, and the limitations of conventional testing frameworks. Among these contaminants, engineered nanomaterials (ENMs) stand out for their unique surface reactivities and transformation pathways, which can significantly alter their behavior and that of co-occurring pollutants. Although many studies have addressed the toxicity and fate of individual ENMs, real-world scenarios often involve complex mixtures, whose combined effects are less investigated. This study addresses this gap by investigating the fate, behavior, and ecological impacts of a mixture of two representative metal oxide ENMs i.e. an industrial TiO2 and a combustion-derived CeO2. This study shows that under environmentally relevant conditions using freshwater mesocosms, these two ENMs undergo primary hetero-aggregation. Co-exposure of the freshwater snail Planorbarius corneus revealed that ENM aggregates (homo- or primary hetero-aggregates) interact with egg layings, potentially affecting early developmental stages, while slight but measurable uptakes were also observed in co-exposed adult snails. Importantly, no quenching of reactive oxygen species generated by the photocatalytic TiO2 was detected in the presence of CeO2, suggesting that the combusted CeO2 does not mitigate potentially TiO2-induced phototoxicity. These findings underscore the importance of considering ENM mixtures in environmental risk assessments and the relevance of mesocosm experiments to capture realistic exposure scenarios. Future studies should prioritize investigating how unique surface reactivities and transformation mechanisms of ENM mixtures shape their ecological impacts throughout their life cycles
Les chélateurs spécifiques du cuivre : une voie pour la thérapie de la maladie de Wilson
No full textInternational audienceCopper specific chelators: a drug candidate for the therapy of Wilson’s disease. Among orphan diseases, some seem more orphan than others... This is the case of Wilson’s disease. While other genetic diseases have attracted the attention of academic or industrial researchers, it must be recognized that this “copper disease”, which requires lifelong treatment of patients, is currently only treated by two old molecules, of moderate efficacy, and having significant adverse effects. It is in this context that a new specific copper chelator, TDMQ20, proved very effective during its evaluation on TX mice, a classic model of this disease which is due to the deficiency of the ATP7B protein, responsible for the elimination of excess copper in the liver. Its pharmacological properties are directly linked to the particular structure of the copper-TDMQ20 complex and make it an effective competitor of the molecules currently in clinical use.Parmi les maladies orphelines, certaines semblent plus orphelines que d’autres... C’est le cas de la maladie de Wilson. Alors que d’autres maladies génétiques ont retenu l’attention des chercheurs universitaires ou industriels, force est de reconnaitre que cette « maladie du cuivre », qui exige un traitement des patients leur vie durant, n’est actuellement traitée que par deux molécules anciennes, d’efficacité modérée et ayant des effets indésirables non négligeables. C’est dans ce contexte qu’un nouveau chélateur spécifique du cuivre, la TDMQ20, s’est avéré très efficace lors de son évaluation sur les souris TX, modèle classique de cette maladie qui est due à la déficience de la protéine ATP7B, en charge de l’élimination de l’excès de cuivre au niveau du foie. Ses propriétés pharmacologiques sont directement liées à la structure particulière du complexe cuivre-TDMQ20 et en font un compétiteur efficace des molécules actuellement en usage clinique
Impact of seasonal snow on the recharge of a mountain karst aquifer under climate change: the Dévoluy case study (Southern Alps, France)
No full textPreprint to HESS (Hydrology and Earth System Sciences) - Discussion started: 9 January 2026International audienceSeasonal snow strongly influences groundwater recharge in mountain aquifers, yet its role in mid-altitude karst systems under climate warming remains poorly quantified. We investigated the Dévoluy karst aquifer (Southern French Alps) to assess how snow controls recharge and how spring discharge may respond to rising temperatures. Using the KarstMod platform, we developed a rainfall–snow–discharge model incorporating a degree-day snow routine to partition precipitation between rainfall and snow, and simulate the snowmelt. The model was calibrated and validated over four contrasting years (two low-snow, one high-snow, and one very high-snow year). Results show that accounting for snow processes is essential to reproduce the observed discharge dynamics, highlighting the dominant role of snow accumulation and melt in controlling both flow timing and magnitude. Under +2 °C and +4 °C warming scenarios, simulated winter flows increase while snowmelt peaks occur earlier, resulting in earlier and more severe summer low-flow periods. August discharge decreases by 28 % to 44 %, respectively, compared to present conditions. These findings demonstrate the critical role of seasonal snow in regulating recharge in mid-altitude karst aquifers and highlight that ongoing warming will substantially reduce summer water availability in mountain regions
Configurational Energy as a Microstructural Descriptor of Failure Precursors in 2D Frictional Granular Materials
No full textInternational audienceLocalized deformation in dense granular materials, often culminating in the formation of shear bands, is a key failure mechanism in geotechnical and material systems. However, predicting the onset of such localization remains a fundamental challenge due to the system's inherent inelasticity and microstructural complexity. In this study, we propose that the evolution of internal configuration—characterized by changes in contact topology and stored potential energy—governs the collective mechanical response and encodes precursors to material failure. To quantify this evolving internal state, we introduce the notion of configurational energy, defined as the change in contact‐scale elastic potential energy resulting from a controlled loading—unloading probe. This metric is first formulated at the contact level and subsequently analyzed at the specimen scale using Discrete Element Method (DEM) simulations of biaxial compression. Our results demonstrate that configurational energy captures the system's sensitivity to perturbations and reflects local instability: both positive and negative values emerge at the contact level, with large magnitudes concentrated near regions of active rearrangement. Despite this local variability, the specimen‐scale configurational response remains strictly negative, and its magnitude increases systematically as the material approaches failure. Notably, spatial localization of configurational energy precedes the formation of macroscopic shear bands with an evolving internal length scale, offering a mesoscale energetic signature of incipient failure. These findings establish configurational energy as a physically grounded descriptor of microstructural evolution and a promising tool for anticipating failure in frictional granular systems
Lithospheric models supported by the Caribbean and Levant examples help rethink transpression at plate boundaries
No full textInternational audienceStrike-slip restraining bends, such as the Levant Fault, belonging to push-up systems and the Jamaican fault network, belonging to duplex systems, display a diversity of fault geometries and deformation patterns that reflect distinct modes of lithospheric-scale strain localization. To investigate the origin of this variability, we develop 3D numerical models of transpressional strike-slip systems using heterogeneous simple shear boundary conditions and thermally-dependent, non-linear rheology. Unlike classical analog or numerical models that impose velocity discontinuities, our approach allows spontaneous fault localization that naturally generates transpression. We systematically explore how the position and geometry of inherited weak zones influence fault development. We show that three distinct strike-slip systems emerge: (1) push-up systems with a single strike-slip fault and outward-propagating thrusts; (2) duplex systems with interacting parallel faults connected by P-shears; and (3) systems of non-interacting parallel faults. These results highlight spontaneous strike-slip localization and how initial heterogeneities control formation and evolution of long-term lithospheric deformation